Pirfenidone is a drug constituted by a small molecule, the chemical name of which is 5-methyl-l-phenyl-2-(1H)-pyridone. It is a non-peptidic synthetic molecule with a molecular weight of 185.23 Dalton. Its chemical formula is C12H11NO, and its structure is known. Currently, pirfenidone is under clinical evaluation as a wide spectrum anti-fibrotic drug. Pirfenidone has anti-fibrotic and anti-inflammatory properties that are reflected in its activity of lowering the expression of TGF-β1, TNF-α, PDGF and most importantly, the expression of different types of collagens. Currently, Phase III studies are being conducted on humans with regard to lung fibrosis, chronic renal failure secondary to kidney glomerulosclerosis, hepatic cirrhosis and breast capsular contracture.
Basic and clinical research works, already published or in process of being published, have shown that pirfenidone lowers the progressive advance of fibrosis lesions. Most importantly, pirfenidone performs said actions in a safe and non-toxic manner. Moreover, it is known that pirfenidone prevents the formation of fibrotic lesions after damage to a given organ, for example liver, skin, kidney, etc.
It is known that one of the mechanisms through which pirfenidone performs its therapeutic effects is through the modulation of the action of several cytokines. Pirfenidone is a potent inhibitor of fibrogenic cytokines and TNF-α. It is well documented that pirfenidone inhibits the excessive biosynthesis and release of several fibrogenic cytokines such as TGF-β1, bFGF, PDGF, and EGF. Zhang S. et al., Australian and New England J. Ophtalmology 26:S74-S76 (1998). Other scientific reports also show that pirfenidone blocks the synthesis and liberation of excessive quantities of TNF-α from macrophages and other cells, Cain et al., Int'l J Immunopharmacology 20:685-695 (1998).
On the other hand, pirfenidone is a drug that has been applied for restoring tissues with fibrotic lesions and preventing fibrotic lesions as well. This compound, per se, is a known compound and its pharmacological effects have been described, for example, in Japanese applications KOKAI Numbers 87677/1974 and 1284338/1976, as an anti-inflammatory agent that includes anti-pyretic and analgesic effects. U.S. Pat. Nos. 3,839,346, published on Oct. 1, 1974; 3,974,281, published on Aug. 10, 1976; 4,042,699, published on Aug. 16, 1977, and 4,052,509, published on Oct. 4, 1977, describe methods for obtaining pirfenidone, as well as its use as anti-inflammatory agent. The anti-fibrotic activity of 5-methyl-1-phenyl-2-(1H)-pyridone is described in Mexican patent 182,266.
New applications of pirfenidone have been discovered that are the object of the instant invention, showing that the compound is active in the reduction of the deleterious effects (breast capsular contracture) observed after the surgical implantation of breast implants in humans.
Moreover, as described and illustrated in the instant invention, pirfenidone is also effective in the regression of chronic renal failure secondary to primary human glomerulosclerosis and hepatic fibrosis.
Modern life is characterized by a cult of vanity and self-esteem both for men and women. For this reason, aesthetic surgery is in high demand nowadays. One of the most requested embodiments in aesthetic surgery is breast implant. Although this type of surgery is every day safer, the presence of side or adverse effects is still common. The deleterious effects observed after the placement of the breast implants are inflammation, capsular contracture and fibrosis development. Several materials have been tested for reducing said side effects.
The current beauty concepts have increased the demand for breast surgery for reconstructive and beauty purposes. However, despite the great usefulness of said medical procedure, one of the most frequent complications of post-surgery is the swelling and contracture of the capsule around the implant. Said complications cause malformation, hardness and breast pain deriving in patient's physical and psychological alterations. The causes and histopathogenesis of capsular contracture are not clearly understood. Various publications mention a variable incidence ranging from 0 to 74% (1), depending on the implantation, the type of implant cover, the surface texture and the anatomic site (2) (subglandular or subpectoral). The causes of these complications can be liquid accumulation in the tissue of the implants bag, intense inflammatory response, sub-clinical infection, age of the patient, foreign materials and the alteration of cellular and molecular mechanisms in the implantation area. When an implant is placed, the body reacts encapsulating it and starting a rejection reaction (3.4) with the formation of a hypertrophic scar (5.6). This immune response produces cytokines and growth factors such as IL-1, IL-6, TNF-α, PDGF and TGF-β1 (7, 8). The presence of myofibroblasts in the capsule structure with alpha-SMA (alpha-smooth muscle actin) production has been reported, wherein the most deformed capsules show the highest alpha-SMA production, suggesting that activated myofibroblasts play a direct part in contracture development (8). It has also been shown that the number of fibroblasts present in the tissue is proportional to contracture thickness (9). In order to reduce fibroblasts activation and wound contracture, steroid infiltration in the wound and in the inner part of the implant has been used with minor complications. Said complications are thin skin, fine tissue atrophy, stratification, blue-skin and implant exposition. However, the side effects of steroids and other drugs used are fairly important and their continuous and prolonged use should be avoided.
Pirfenidone (5-methyl-1-phenyl-2-(1H)-pyridone) (PFD) has shown to be efficacious in the prevention of fibrosis formation both in vitro as well as in vivo. It inhibits lung fibrosis (10), peritoneal adherence (11), liver cirrhosis (12, 13), uterine fibromyoma (14), kidney fibrosis (15), keloid scars (16) and delays the development of central nervous system tumors. Pirfenidone can also highly specifically inhibit cytokines such as TNF-alpha, FGF, PGDF and TGF-beta in the human fibroblast blocking the G1 phase of the cellular cycle. Because breast implant induces fibrosis and inflammation and because pirfenidone has shown anti-fibrotic and anti-inflammatory characteristics, the instant invention evidences the effect of pirfenidone in the inhibition of the capsular contracture in breast implant in humans.
Tumor Necrosis Factor-alpha (TNF-α)
                The TNF protein family includes TNF-α, TNF-β, Fas ligand, CD40 ligand, OX-40, RANK-L (receptor activator of nuclear factor kappa-B ligand) and TRAIL (TNF-related apoptosis inducing ligand).        For historical reasons it is denominated TNF-α for distinguishing it from TNF-β or lymphotoxin.        Originally it was identified as a substance present in the serum of animals treated with bacterial endotoxin (lipopolysaccharide or LPS) causing in vivo tumor necrosis (its name is derived from this).        The main TNF cellular source is activated mononuclear phagocytes although antigen stimulated T lymphocytes, NK lymphocytes and mastocytes can also secrete it.        TNF is the main mediator of the acute inflammatory response to gram negative bacteria and other infectious microorganisms.        Its main biological action is to stimulate the attraction of neutrophils and monocytes to the infection zones and to activate said cells for microorganism eradication.        Mononuclear phagocytes come in two forms: anchored to membrane, and soluble.        The TNF anchored to membrane form is separated by a membrane associated metalloprotease (MMP-MT) and is released. Three of these polypeptides unite and a TNF circulating protein is formed.        There are two TNF receptors (TNF-RI and TNF-RII).        Type I receptor can stimulate the gene expression of inflammatory mediators or induce apoptosis.        The pro-inflammatory or anti-apoptotic route is initiated by the union of TRADD (TNF Receptor-Associated Death Domain) to the intracytoplasmatic domain of the TNF receptor followed by TRAF-2 (TNF Receptor-Associated Factors) or RIP-1 (Receptor Interacting Protein), leading to NF-kB and Ap-1 dependent gene expression.        However, if instead of binding to TRAF or RIP it binds to FADD (FAS-Associated Death Domain), this causes apoptosis because it cuts pro-Caspase 8 and said pro-Caspase 8 in turn activates caspase effectors such as Caspase 3, this being the apoptotic route.        If type II receptor binds directly to TRAF, it causes gene expression of inflammatory mediators.        The genes induced by TNF receptors code mainly for inflammation mediators and anti-apoptotic proteins.        Based on the above, use of TNF-α receptor blockers is one of the strategies designed to obliterate inflammatory response.        
Thus, in the instant invention it is described and shown that pirfenidone has an extremely potent and selective TNF-α inhibiting action. This information is shown in FIG. 6.
Transforming Growth Factor beta (TGF-β)
                TGF-β was isolated from human platelets in the 1980's and was identified as a product of cells transformed by the murine sarcoma virus. It was later named transforming growth factor beta for its capacity to cause a phenotypic transformation in an epithelial cells culture because it induced reversible fibroblasts transformation.        TGF-β main action in the immune system is to inhibit lymphocytes proliferation and activation.        Outside the immune system, TGF-β is considered the main trigger for the production of extracellular matrix components, inducing fibrosis through the stimulation of the production of collagen type I, III and IV, fibronectin, laminin and proteoglycans. It is increased in hepatic, lung and renal fibrosis both in experimental models as well as in humans.        It is synthesized as an inactive dimeric precursor.        Active TGF-β binds to the extracellular domain of type II receptor. Ligand binding promotes TβRII intracytoplasmatic autophosphorylation because of its serine/threonine kinase activity, and in turn TβRII phosphorylates type I receptor, triggering thus Smads (signal transducing intracellular molecules) activation, able to translocate to the nucleus and regulate transcription of target genes such as Smad 7, PAI-I collagen I, PDGF an TGF-β itself        Smad2/3-Smad4 complexes in the nucleus can associate with transcription co-activators and co-repressors.        Three co-repressors are identified for Smad: TGIF protein and two related proteins denominated SnoN and c-Ski. All of them are important repressors of the TGF-β signaling route, although their function in hepatic fibrosis is not fully described.        
Thus in the instant invention it is described and shown that pirfenidone has an extremely potent and selective inhibiting action against TGF-β production. This information is shown in FIG. 5.